HomeMy WebLinkAboutGPA 09-01; ROBERTSON RANCH PA 22; NOISE ANALYSIS; 2009-10-05~
URBAN
CROSSROADS
5411 Avenida Encinas, Suite 100
Carlsbad, CA 92008
Prepared by:
Jeremy Louden
J.T. Stephens, INCE
Prepared for:
Mr. Adam Pevney
BROOKFIELD HOMES
12865 Pointe Del Mar, Suite 200
Del Mar, CA 92014-3859
ROBERTSON RANCH PA 22-
OFFICE BUILDING NOISE ANALYSIS
CITY OF CARLSBAD, CALIFORNIA
October 5, 2009 Revised
JN: 06679-06
JL:JS:dl
..
TABLE OF CONTENTS
SECTION PAGE
1.0 EXECUTIVE SUMMARY.................................................................................. 1
1.1 Interior Noise Mitigation.......................................................................... 1
1.2 Potential Operational Noise Impacts...................................................... 2
2.0 INTRODUCTION ............................................................................................... 4
3.0 NOISE FUNDAMENTALS................................................................................. 7
3.1 Noise Descriptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . . . . . . . .. . .. .. . . . .. .. . .. .. .. . . . . . . . . .. . . . . . 7
3.2 Traffic Noise Prediction........................................................................... 7
3.3 Noise Control.......................................................................................... 8
3.4 Ground Absorption.................................................................................. 8
3.5 Noise Barrier Attenuation........................................................................ 9
4.0 NOISE STANDARDS ....................................................................................... 10
4.1 Noise Element Criteria............................................................................ 1 O
4.2 Noise Ordinance Criteria . . .. . . . .. . ... . .. .. . . .. . . . . . . . .. . .. .. . . . .. . . . . . . . . . . . .. ... .. .. . .. . . .. .. . . 10
5.0 METHODS AND PROCEDURES .................... ..... .............. ... ........................... 12
5.1 FHWA Traffic Noise Prediction Model.................................................... 12
5.2 Traffic Noise Prediction Model Inputs..................................................... 12
6.0 EXTERIOR NOISE ANALYSIS......................................................................... 16
7.0 INTERIOR NOISE ANALYSIS........................................................................... 18
7 .1 Interior Noise Reduction Methodology................................................... 18
7.2 Calculated Interior Noise Reductions..................................................... 18
7.3 Interior Noise Level Assessment............................................................ 19
8.0 STATIONARY NOISE SOURCE OPERATIONS IMPACTS............................ 25
8.1 Project Related Stationary Source Noise............................................... 25
8.2 Reference Noise Level Impacts . . . . . .. .. .. . . . .. . . .. . . . .. . . . .. . . . .. .. . .. .. . . . . . .. .. . .. .. .. . . . 25
8.3 Project Only Stationary Source Noise Impacts . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . 26
APPENDICES
CITY OF CARLSBAD NOISE MATRIX . . . . . . . . .. . . .. .. .. . . . . . .. . .. . . . . .. .. .. . .. . . . . .. . . . .. .. .. . . . ... . . . . .. .. . A
EXTERIOR ANALYSIS PREDICTION MODEL INPUTS AND
CALCULATIONS FOR BUILDOUT SCENARIO.......................................................... B
INTERIOR NOISE REDUCTION CALCULATIONS................................................. C
STATIONARY NOISE SOURCE CALCULATIONS................................................ D
LIST OF EXHIBITS
EXHIBIT PAGE
2-A LOCATION MAP................................................................................................ 5
2-B SITE PLAN . . . . . . . . . .. . . . . .. . . . . . .. . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . .. . . . . . . . ... .. . . . . . . . .. . . . . . . . . 6
8-A PROPERTY LINE NOISE IMPACTS................................................................ 27
LIST OF TABLES
TABLE PAGE
5-1 ROADWAY PARAMETERS.............................................................................. 13
5-2 HOURLY TRAFFIC FLOW DISTRIBUTION .................................................... 14
6-1 FUTURE EXTERIOR NOISE LEVELS (dBA CNEL) ....................................... 17
7-1 INTERIOR NOISE REDUCTION CALCULATIONS (dBA CNEL) .................... 20
7-2 FIRST FLOOR INTERIOR NOISE IMPACTS (dBA CNEL).............................. 21
7-3 SECOND FLOOR INTERIOR NOISE IMPACTS (dBA CNEL)......................... 22
7-4 THIRD FLOOR INTERIOR NOISE IMPACTS (dBA CNEL) ............................. 23
ROBERSTON RANCH PA 22-OFFICE BULDING
NOISE ANALYSIS
CITY OF CARLSBAD, CALIFORNIA
1.0 EXECUTIVE SUMMARY
This noise analysis has been completed to determine the noise exposure and the
necessary interior noise mitigation measures for the proposed Robertson Ranch Planning
Area (PA) 22 Office Building. The proposed project includes an approximate 66,000
square foot, 3-story office building. The proposed project is located along the existing
alignment of Cannon Road in the City of Carlsbad.
The results of this analysis indicate that the future vehicle noise from Cannon Road is the
principal source of community noise that will impact the site. Based on the future traffic
projections along Cannon Road, portions of the site will experience worse-case
unmitigated exterior noise levels as high as 68.3 dBA CNEL at each floor of the office
building.
Architectural plans are not available at this time; therefore two worse-case scenarios
were developed to represent the office spaces. One scenario consisted of a 20 x 20 foot
room with two 4 x 5 foot windows. The second scenario consisted of a 15 x 20 foot
room with one 4 x 5 foot window. Once the actual architectural plans are available, the
floor plans should be verified for consistency with this report. To reduce exterior traffic
noise impacts and to meet the City of Carlsbad interior noise standard of 55 dBA CNEL,
the project should p~ovide the noise mitigation measures listed below:
1.1 Interior Noise Mitigation
• Provide standard dual-glazed windows with a minimum Sound Transmission
Class (STC) rating 26 for all first, second and third floor windows.
• All window and door assemblies used throughout the project shall be free of cut
1
outs and openings and shall be well fitted and well weather-stripped.
• Provide a windows closed condition requiring a means of mechanical ventilation
for all units to meet the City and/or Uniform Building Code (UBC) requirements
stating that in lieu of exterior openings for natural ventilation, a mechanical
ventilating system may be provided (i.e., air conditioning). Such a system shall
be capable of providing two air changes per hour with minimum outside fresh air
requirements.
• Provide exterior walls with a minimum Sound Transmission Class (STC) rating
of 46. Typical walls with this rating will have 2x4 studs or greater, 16" o.c. with
R-13 insulation, a minimum 7/8" exterior surface of cement plaster and a
minimum interior surface of 1/2" gypsum board. Masonry block or concrete tip-
up assemblies will perform better than the above described wood assembly and
would be an acceptable alternative.
No additional interior noise mitigation is required to meet the City of Carlsbad 55 dBA
CNEL interior noise standards.
1.2 Potential Operational Noise Impacts
The nearest noise sensitive areas are the existing single-family residential land
uses to the south of the project site. For the purposes of the analysis, noise
levels were assessed at the residences during nighttime hours which are
considered a worst-case scenario.
Calculations were completed to assess the nighttime noise level impacts from the
proposed project to the observers located at the single-family residences to the
south. With the project design features including the louvers on the mechanical
room facing the eastern and/or western property line and the mechanical
equipment enclosure is at least one-foot in height above the proposed
equipment. The project only nighttime noise level projection is expected to be 42.7
2
dBA Leq at the nearest residential noise sensitive use located approximated 215
feet to the south.
The City of Carlsbad has not established a quantitative threshold for operational
noise levels from fixed "point" sources. The City determines if the proposed use
is compatible with the existing surrounding land uses based upon the results of
an acoustical assessment. It should be noted: the 42. 7 dBA Leq noise level is
below both the City's exterior 65 dBA CNEL and interior 45 dBA CNEL
requirements for residential land uses. Because CNEL is used only for
determining mobile noise sources over a twenty-four hour period the one hour
Leq is a more appropriate and restrictive standard.
By comparison, the anticipated property line noise level is also below the most
restrictive residential property line threshold established by the County of San Diego
of 45 dBA Leq during the nighttime hours. Therefore no impacts are anticipated
from the proposed mechanical equipment in PA-22. Furthermore, the analysis does
not take into account the additional noise level reductions from the existing wall
located at the boundary of the Rancho Carlsbad community or the project's
proposed wall located between the residences and the noise sources. Those walls
would further reduce the noise levels below 40 dBA Leq, which is similar to the
existing nighttime ambient conditions.
With the project design features and the recommended interior noise mitigation measures
provided in this study, the proposed project will meet the City of Carlsbad noise standards
for commercial development.
3
2.0 INTRODUCTION
This report presents the results of a final noise study for Planning Area 22 of the
Robertson Ranch Residential Development. This final noise study outlines the project,
provides basic information regarding the fundamentals of traffic noise, describes local
noise guidelines, provides the study methods and procedures for traffic noise analysis,
and evaluates the future exterior and interior noise environments. The proposed project
is located south of Cannon Road and east of El Camino Real in the City of Carlsbad as
shown on the Location Map, Exhibit 2-A. The proposed Robertson Ranch Planning Area
22 Development will be developed with an approximate 66,000 square foot, 3-story office
building as shown on Exhibit 2-8.
The recommendations for control of the noise impacts for exterior and interior areas were
designed to satisfy the City of Carlsbad noise standards.
4
3.0 NOISE FUNDAMENTALS
Noise has been simply defined as "unwanted sound". Sound becomes unwanted when
it interferes with normal activities, when it causes actual physical harm or when it has
adverse effects on health. Noise is measured on a logarithmic scale of sound pressure
level known as a decibel (dB). A-weighted decibels (dBA) approximate the subjective
response of the human ear to broad frequency noise sources by discriminating against
very low and very high frequencies of the audible spectrum. They are adjusted to
reflect only those frequencies which are audible to the human ear.
3.1 Noise Descriptors
Equivalent sound levels are not measured directly but are calculated from sound
pressure levels typically measured in A-weighted decibels (dBA). The equivalent
sound level (Leq) represents a steady state sound level containing the same
total energy as a time varying signal over a given sample period. The peak hour
Leq is the noise metric used by Caltrans for all traffic noise impact analyses.
The Community Noise Equivalent Level (CNEL) is the weighted average of the
intensity of a sound, with corrections for time of day, and averaged over 24
hours. The time of day corrections require the addition of 5 decibels to sound
levels in the evening hours between 7 p.m. and 10 p.m. and the addition of 10
decibels to sound levels at night between 10 p.m. and 7 a.m. These additions
are made to account for the noise sensitive time periods during night hours when
sound appears louder. CNEL values do not represent the actual sound level
heard at any particular time, but rather represents the total sound exposure. The
City of Carlsbad relies on the CNEL noise standard to assess transportation
related impacts on noise sensitive land uses.
3.2 Traffic Noise Prediction
The level of traffic noise depends on three primary factors: (1) the volume of the
traffic, (2) the speed of the traffic and (3) the number of trucks in the flow of
traffic. Generally, the loudness of traffic noise is increased by heavier traffic
7
volumes, higher speeds and a greater number of trucks. Vehicle noise is a
combination of the noise produced by the engine, exhaust and tires.
Because of the logarithmic nature of traffic noise levels, a doubling of the traffic
noise (acoustic energy) results in a noise level increase of 3 dBA. Based on the
FHWA community noise assessment criteria, this change is "barely perceptible".
In other words, doubling the traffic volume (assuming that the speed and truck
mix do not change) results in a noise increase of 3 dBA. The truck mix on a
given roadway also has a significant effect on community noise levels. As the
number of heavy trucks increases and becomes a larger percentage of the
vehicle mix1 adjacent noise levels increase.
3.3 Noise Control
Noise control is the process of obtaining an acceptable noise environment for a
particular observation point or receiver by controlling the noise source,
transmission path, receiver or all three. This concept is known as the source-
path-receiver concept. In general, noise control measures can be applied to any
and all of these three elements.
3.4 Ground Absorption
To account for the ground-effect attenuation (absorption), two types of site
conditions are commonly used in traffic noise models, soft site and hard site
conditions. Soft site conditions account for the sound propagation loss over
natural surfaces such as normal earth and ground vegetation. A drop-off rate of
4.5 dBA per doubling of distance is typically observed over soft ground with
landscaping. On the other hand, a 3.0 dBA drop-off rate is observed for hard
site conditions, such as asphalt, concrete, stone and very hard packed earth. In
order to predict a worse-case analysis, hard site conditions were utilized.
8
3.5 Noise Barrier Attenuation
Effective noise barriers can reduce noise levels py 10 to 15 decibels, cutting the
loudness of traffic noise in half. Noise barriers are most effective when placed
close to the noise source or receiver. However, noise barriers do have
limitations. For a noise barrier to work, it must be high enough and long enough
to block the view of a road. Noise barriers do little good for homes on a hillside
overlooking a road or for buildings which rise above the barrier. A noise barrier
can achieve a 5 decibels noise level reduction when it is tall enough to break the
line-of-sight.
9
4.0 NOISE STANDARDS
The City of Carlsbad has identified two separate types of noise sources: (1) mobile, and
(2) stationary. To control mobile or transportation related noise sources such as
freeways, airport and railroads, the City of Carlsbad has established guidelines for
acceptable community noise levels in the Noise Element of the General Plan. The most
effective method to control community noise impacts from non-transportation noise
sources (such as air conditioning units, etc.) is through the application of a community
noise ordinance
4.1 Noise Element Criteria
The City of Carlsbad has adopted interior and exterior noise standard as part of
the General Plan Noise Element for assessing the compatibility of land uses with
transportation related noise impacts. For noise sensitive commercial land uses,
the City has adopted a policy which has established a "normally acceptable"
exterior noise level goal of 65 dBA CNEL for the outdoor areas and an interior
noise level of less than 55 dBA CNEL. However, the City has also established a
"conditionally acceptable" policy goal of up to 75 dBA CNEL. The City of Carlsbad
noise standard matrix is included in Appendix "A", In the context of this noise
analysis, the noise impacts associated with the project are controlled by the City
noise element.
4.2 Noise Ordinance Criteria
The generation of noise for certain types of land uses could cause potential land
use incompatibility. Noise generating uses or devices should be considered
during normal project review. The following requirements should ensure that
noise generated from specific land uses or devices will be compatible with
adjacent land uses.
10
NG.1 Prior to approval of any permits, an Acoustical Analysis Reporl and
appropriate plans shall be submitted describing the noise generation
potential of the proposed project, and proposed noise attenuation
measures to assure that an environment which is free from excessive or
harmful noise is achieved and maintained. The repot1 shall be prepared
under the supervision of a certified acoustical consultant and submitted to
the Planning Director for review and approval. The approved attenuation
features shall be Incorporated into the plans and specifications of the
proposed project.
NG.2 Prior to approval of the proposed project or issuance of any permit, a
Noise Report shall be submitted to the City, which illustrates the feasibility
of the exterior mitigation measures required to achieve City Noise
Standards.
11
5.0 METHODS AND PROCEDURES
The following section outlines the methods and procedures used to model and analyze
the future noise environment.
5.1 FHWA Traffic Noise Prediction Model
The projected roadway noise impacts from vehicular traffic were projected using a
computer program that replicates the Federal Highway Administration (FHWA)
Traffic Noise Prediction Model-FHWA-RD-77-108 (the "FHWA Model"). The
FHWA Model arrives at a predicted noise level through a series of adjustments to
the Reference Energy Mean Emission Level (REMEL). Adjustments are then
made to the reference energy mean emission level to account for; the roadway
classification (e.g., collector, secondary, major and arterial), the roadway active
width (i.e., the distance between the center of the outermost travel lanes on each
side of the roadway), the total average daily traffic (ADT), the travel speed, the
percentages of automobiles, medium trucks and heavy trucks in the traffic volume,
the roadway grade, the angle of view (e.g., whether the roadway view is blocked),
the site conditions ("hard" or "soft" relates to the absorption of the ground,
pavement or landscaping) and the percentage of total average daily traffic (ADT)
which flows each hour throughout a 24-hour period.
5.2 Traffic Noise Prediction Model Inputs
The average daily traffic volumes used for the noise analysis are presented in
Table 5-1 and were provided by the Transportation Analysis for Robertson Ranch
-Urban Systems Associates, Inc. dated 9/1/05.
Tabie 5-2 presents the hourly traffic flow distribution (vehicle mix) used for this
analysis. For the purpose of this analysis 80% of an vehicles were assigned during
the daytime hours of 7 a.m. to 7 p.m., 7% during the evening hours of 7 p.m. to 10
12
TABLE 5-1
ROADWAY PARAMETERS
ROADWAY ROAD
CLASSIFICATION
I Cannon Road I Major 4-Lane Road l
'Average Daily Traffic {ADTJ for bulldout condition was based
on year 2030 Buildout ADT
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{ADT)1
19,000
MODELED VEHICLE
SPEED
I 55 I
TABLE 5-2
HOURLY TRAFFIC FLOW DISTRIBUTION
DAYTIME EVENING NIGHT TOTAL% TRAFFIC
MOTOR-VEHICLE TYPE (7 AM TO 7 PM) (7 PM TO 10 PM) (10 PM TO 7 AM) FLOW
Cannon Road
Automobiles 80.0% 7.0% 13.0% 96.00%
Medium Trucks 80.0% 7.0% 13.0% 2.00%
Heavy Trucks 80.0% 7.0% 13.0% 2.00%
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14
p.m. and 13% during the nighttime hours of 10 p.m. to 7 a.m. The vehicle mix
provides the hourly distribution percentages of automobile, medium trucks and
heavy trucks for input into the FHWA Model.
15
6.0 EXTERIOR NOISE ANALYSIS
Using the FHWA traffic noise prediction model and the input parameters described in
Section 5 of this report, calculations of the expected future noise impacts were
completed. The exterior noise levels were analyzed for the worse-case future buildout
conditions along Cannon Road.
The buildout analysis was modeled assuming future Year 2030 traffic volumes and the
traffic speed of 55 miles per hour along Cannon Road. At this time, the project does not
propose exterior use areas at the office building. The outdoor use area will be located
south of the proposed building and will be shielded form Cannon Road. The results of
the traffic noise prediction model were used to analyze the interior noise levels at all three
floors of the office building. The results are provided in Table 6-1. The FHWA
calculations for first, second and third floor future year 2030 conditions are provided in
Appendix "B".
16
TABLE 6-1
FUTURE EXTERIOR NOISE LEVELS (dBA CNEL)
UNMITIGATED EXTERIOR NOISE LEVEL
RECEPTOR FIRST FLOOR SECOND FLOOR THIRD FLOOR
1 68, 1 681 68.0
2 68,3 68.2 68,1
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7.0 INTERIOR NOISE ANALYSIS
The interior noise level is the difference between the predicted exterior noise level at the
building facade and the noise reduction of the structure. Typical building construction will
provide a noise reduction of approximately 12 dBA with "windows open" and a minimum
20 dBA noise reduction with "windows closed". Several methods are used to improve
interior noise reduction, including: (1) weather-stripped solid core exterior doors; (2)
upgraded dual glazed windows; (3) mechanical ventilation/air conditioning and (4) exterior
wall/roof assembles free of cut outs or openings.
New construction will generally produce a "windows closed" noise reduction ranging from
25 dBA to 30 dBA. However, sound leaks, cracks and openings within the window
assembly Cc!n greatly diminish its effectiveness in reducing noise.
7.1 Interior Noise Reduction Methodology
The noise reduction characteristics of a building are determined by combining
the transmission loss of each of the building components that make up the
building. Each unique component has a transmission loss value. For office
buildings, the critical building components include the roof, walls, windows, doors
and insulation characteristics. The total noise reduction is dependent upon the
transmission loss of each element and the surface area of that element in
relation to the total surface area of the room.
To account for the acoustic energy absorbed within a room, the absorption
coefficients for individual surface areas such as drywall and carpet are used to
calculate the interior room effects. The calculated building noise reduction
includes both the transmission loss associated with the exterior wall assembly
and the room absorption characteristics.
7.2 Calculated Interior Noise Reductions
Noise reduction calculations were used to estimate the ''windows closed" interior
noise levels for all floors of the office building. Architectural plans are not available
at this time; therefore two worse-case scenarios were developed to represent the
18
hotel rooms. One scenario consisted of a 20 x 20 foot room with two 4 x 5 foot
windows. The second scenario consisted of a 15 x 20 foot room with one 4 x 5
foot window .. These two worse-case scenarios represent typical office space.
The calculations assumed building construction that includes dual glazed
windows with standard windows with a minimum Sound Transmission Class
Rating (STC) of 26.
As shown on Table 7-1, with standard windows the interior noise reduction will
range from 33.2 to 34.6 dBA CNEL. The interior noise reduction calculations
with standard windows are included in Appendix "C".
7.3 Interior Noise Level Assessment
Tables 7-2 through 7-4 present the future first, second and third floor interior noise
levels. The exterior noise levels at the building facades will range from 68.0 to 68.3
dBA CNEL. The calculations show that the "windows open" condition will not
provide adequate interior noise mitigation for rooms affected by Cannon Road.
To meet the 55 dBA CNEL interior noise standard, an interior noise level reduction
ranging from 23.1 to 23.3 dBA is required. The noise levels shown on Tables 7-2
through 7-4 show that with a "windows closed" condition, requiring a means of
mechanical ventilation and standard windows with a STC rating 26 or higher, the
future interior noise levels will be below the City of Carlsbad's 55 dBA CNEL
interior noise level standard.
The calculated interior noise reduction requires that exterior walls have a
minimum Sound Transmission Class (STC) rating of 46. Typical walls with this
rating will have 2x4 studs or greater, 16" o.c. with R-13 insulation, a minimum 7 /8"
exterior surface of cement plaster and a minimum interior surface of 1/2" gypsum
board. Masonry or concrete tip-up assemblies perform better than the wood
assembly described above and would be an acceptable alternative. Interior wall
finish shall be at least 1/2-inch thick gypsum wallboard or plaster. Ceilings shall
be finished with gypsum board or plaster that is at least 1 /2 inch thick.
In addition, provide a windows closed condition requiring a means of mechanical
ventilation for all units to meet the City and/or Uniform Building Code (USC)
19
TABLE 7-1
INTERIOR NOISE REDUCTION CALCULATIONS (dBA CNEL)
SCENARIO ROOM
1 OFFICE SPACE
2 OFFICE SPACE
1 Interior noise reduction calculations with standard
windows (STC 26) included in Appendix "C."
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NOISE REDUCTION
WITH ST AN DARO
WINDOWS (dBA CNEL) 1
33.2
34.6
TABLE 7-2
FIRST FLOOR INTERIOR NOISE IMPACTS (dBA CNEL)
INTERIOR NOISE LEVEL FOR
NOISE WINDOWS
IMPACTS AT
RECEPTOR FACADE OPEN 1 CLOSED2
1 68.1 56.1 34.9
2 68.3 56.3 35.1
1 A minimum of 12 dBA noise reduction ls assumed with a windows open condition
1 With the worse-case calculated interior noise reduction with a
windows closed condition and standard windows presented in Table 7-1
REQUIRED
INTERIOR
NOISE
REDUCTION
23.1
23.3
3 Includes standard windows with a minimum sound transmission class (STC) rating of 26.
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WORSE-CASE
CALCULATED
INTERIOR NOISE
REDUCTION3
33.2
33.2
TABLE 7-3
SECOND FLOOR INTERIOR NOISE IMPACTS (dBA CNEL)
INTERIOR NOISE LEVEL FOR
NOISE WINDOWS
IMPACTS AT
RECEPTOR FACADE OPEN1 I CLOSED2
I
1
I
68.1
I
56.1
I
34.9
I 2 68.2 56,2 35.0
1 A minimum of 12 dBA noise reduction Is assumed with a windows open conditlon
2 With the worse-case calculated interior noise reduction with a
windows closed condition and standard windows presented in Table 7-1
REQUIRED
INTERIOR
NOISE
REDUCTION
23, 1
23.2
3 Includes standard windows with a minimum sound transmission class (STC) ratmg of 26.
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22
I
WORSE-CASE
CALCULATED
INTERIOR NOISE
REDUCTION3
33.2
I 33.2
TABLE 7-4
THIRD FLOOR INTERIOR NOISE IMPACTS (dBA CNEL)
INTERIOR NOISE LEVEL FOR
NOISE WINDOWS
IMPACTS AT
RECEPTOR FACADE OPEN 1 CLOSED2
1 68.1 56.1 34.9
2 68.1 56.1 34.9
'A minimum of 12 dBA noise reduction is assumed with a windows open condition
2 With the worse-case calculated interior noise reduction with a
windows closed condition and standard windows presented in Table 7-1
REQUIRED
INTERIOR
NOISE
REDUCTION
23.1
23.1
3 Includes standard windows with a minimum sound transmission class (STC) rating of 26
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23
WORSE-CASE
CALCULATED
INTERIOR NOISE
REDUCTION3
33.2
33.2
requirements stating that in lieu of exterior openings for natural ventilation, a
mechanical ventilating system may be provided (i.e., air conditioning). Such a
system shall be capable of providing two air changes per hour with minimum
outside fresh air requirements. It should be noted: once the actual architectural
plans are available, the floor plans should be verified for consistency with this
report.
24
8.0 STATIONARY NOISE SOURCE OPERATIONS IMPACTS
This section examines the potential stationary noise source impacts associated with the
operation of the mechanical equipment associated with the Robertson Ranch PA 22 Office
Building.
8.1 Project Related Stationary Source Noise
The nearest noise sensitive areas are the existing residential land uses in the
Rancho Carlsbad community to the south of the project site. For the purposes of
the analysis, impacts were assessed at the residences during nighttime hours
which are considered a worst-case scenario.
8.2 Reference Noise Level Impacts
In order to evaluate the mechanical room stationary source noise impacts,
reference noise level measurements taken at a similar office building in Vista,
California in June, 2008 were utilized. The measurements include the cycling on
and off of the mechanical equipment over a 20 minute period. The unshielded
noise levels were measured at 81.8 dBA Leq at a distance of 15 feet from the
mechanical equipment room. To predict the worst-case future noise environment, a
continuous reference noise level of 82 dBA at 15 feet was used to represent the
mechanical equipment system. Even though the mechanical system will cycle on
and off throughout the day, this approach presents the worst-case noise condition.
In addition, these units have been designed to provide cooling during the peak
summer daytime periods, and it is unlikely that the unit will be operating
continuously throughout the noise sensitive nighttime periods.
25
8.3 Project Only Stationary Source Noise Impacts
Based upon the reference noise levels provided above, it is possible to project noise
impacts from the proposed mechanical equipment. The noise level projections
were calculated based on the site plan showing the locations of the different noise
sources, design features and receptor locations. As a design feature the project is
not installing air flow vents, or louvers, on the southern fa9ade of the mechanical
room. The louvers or air flow vents will be located on the eastern and/or western
portion of the mechanical room as shown on the site plans dated June, 2009.
Additionally, the project is extending the mechanical room's exterior walls at least
one-foot above the equipment. This is being done to further reduce noise levels.
The stationary source noise prediction calculations are included in Appendix "D."
Calculations were completed to assess the nighttime noise level impacts from the
proposed project to the observers located at in the Rancho Carlsbad community to
the south. With the project design features including the louvers on the
mechanical room facing the eastern and/or western property line and the
mechanical equipment enclosure is at least one-foot in height above the
proposed equipment. The project only nighttime noise level projection is expected
to be 42. 7 dBA Leq at the nearest residential noise sensitive use located
approximated 215 feet to the south. The distance from the mechanical equipment
and property line to the south along with the resultant noise level is shown
graphically in Exhibit 8-A.
The City of Carlsbad has not established a quantitative threshold for operational
noise levels from fixed "point" sources. The City determines if the proposed use is
compatible with the existing surrounding land uses based upon the results of an
acoustical assessment. It should be noted: the 42.7 dBA Leq noise level is below
both the City's 65 dBA CNEL exterior and 45 dBA CNEL interior requirements for
residential land uses. Because CNEL is used only for determining mobile noise
26
..
sources over a twenty-four hour period the one hour Leq is a more appropriate and
restrictive standard.
The City of Carlsbad does not have a property line standard for operational sources
therefore the project's operational noise levels were compared to the County of San
Diego Noise Ordinance. The County of San Diego Noise Ordinance Section 36.404
establishes an operational property line noise limit for residential uses, zoned RM, of
55 dBA Leq for daytime hours of 7 a.m. to 10 p.m. and 50 dBA Leq during the noise
sensitive nighttime hours of 10 p.m. to 7 a.m. For commercial zoned property the
County of San Diego Noise Ordinance Section 36.404 applies an operational
property line noise limit of 60 dBA Leq for daytime hours of 7 a.m. to 10 p.m. and 55
dBA Leq during the noise sensitive nighttime hours of 10 p.m. to 7 a.m. The sound
level limit at a location on a property line boundary between two zoning districts is
the arithmetic mean of the respective limits for the two districts. Therefore,
operations from PA 22 would need to meet a worse-case nighttime standard of 52.5
dBA Leq (arithmetic mean between 50 dBA for residential and 55 dBA for
commercial).
By comparison, the anticipated property line noise level is also below the most
restrictive residential property line threshold established by the County of San Diego
of 45 dBA Leq during the nighttime hours. Therefore no impacts are anticipated
from the proposed mechanical equipment in PA-22. Furthermore, the analysis does
not take into account the additional noise level reductions from the existing wall
located at the boundary of the Rancho Carlsbad community or the project's
proposed wall located between the residences and the noise sources. Those walls
would further reduce the noise levels below 40 dBA Leq, which is similar to the
existing nighttime ambient conditions.
28
\
APPENDIX A
CITY OF CARLSBAD NOISE STANDARDS
APPENDIX 8
EXTERIOR ANALYSIS PREDICTION MODEL INPUTS
AND CALCULATIONS FOR BUILDOUT SCENARIO
FHWA-RD-77-108 HIGHWAY NOISE PREDICTION MODEL (CALVENO)
Scenario: First Floor Facade Project Name: Robertson Ranch PA 22
Road Name: Cannon Road Job Number: 6679
Lot Number: Northwest Corner Analyst: J.Stephens
SITE SPECIFIC INPUT DATA NOISE MODEL INPUTS
Highway Data Site Conditions (Hard= 10, Soft= 15)
Average Daily Traffic (Adt): 19,000 vehicles Autos: 15
Peak Hour Percentage: 10% Medium Trucks (2 Axles): 15
Peak Hour Volume: 1,900 vehicles Heavy Trucks (3+ Axles): 15
Vehicle Speed: 55 mph Vehicle Mix
Near/Far Lane Distance: 54 feet Vehicle Type I Day !Evening! Night I Daily
Site Data Autos: 80.0% 7.0% 13.0% 96.00%
Barrier Height: 0.0 feet Medium Trucks: 80.0% 7.0% 13.0% 2.00%
Barrier Type (0-Wa/1, 1-Berm): 0.0 Heavy Trucks: 80.0% 7.0% 13.0% 2.00%
Centerline Dist. to Barrier: 102.0 feet Noise Source Elevations (in feet)
Centerline Dist. to Observer: 102.0 feet Autos: 0.000
Barrier Distance to Observer: 0.0 feet Medium Trucks: 2.297
Observer Height (Above Pad): 5.0 feet Heavy Trucks: 8.006 Grade Adjustment: 0.0
Pad Elevation: 0.5 feet
Road Elevation: 0.0 feet Lane Equivalent Distance (in feet)
Road Grade: 0.0% Autos: 98.515
Left View: -90.0 degrees Medium Trucks: 98.414
Right View: 90.0 degrees Heavy Trucks: 98.393
FHWA Noise Model Calculations
Vehicle Type I REMEL I Traffic Flow I Distance I Finite Road I Fresnel I Barrier Atten I Berm Atten
Autos: 72.73 -0.10 -4.52 -1.20 -4.75 0.000 0.000
Medium Trucks: 79.85 -16.91 -4.51 -1.20 -4.86 0.000 0.000
Heavy Trucks: 83.81 -16.91 -4.51 -1.20 -5.13 0.000 0.000
Unmitigated Noise Levels (without Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.9 65.1 60.6 58.5 66.5 66.8
Medium Trucks: 57.2 55.5 50.9 48.8 56.8 57.1
Heavy Trucks: 61.2 59.4 54.9 52.8 60.8 61.0
Vehicle Noise: 68.3 66.5 62.0 59.9 67.9 68.1
Mitigated Noise Levels (with Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.9 65.1 60.6 58.5 66.5 66.8
Medium Trucks: 57.2 55.5 50.9 48.8 56.8 57.1
Heavy Trucks: 61.2 59.4 54.9 52.8 60.8 61.0
Vehicle Noise: 68.3 66.5 62.0 59.9 67.9 68.1
Thursday, April 16, 2009
FHWA-RD-77-108 HIGHWAY NOISE PREDICTION MODEL (CALVENO)
Scenario: First Floor Facade Project Name: Robertson Ranch PA 22
Road Name: Cannon Road Job Number: 6679
Lot Number: Northeast Corner Analyst: J.Stephens
SITE SPECIFIC INPUT DATA NOISE MODEL INPUTS
Highway Data Site Conditions (Hard= 10, Soft= 15)
Average Daily Traffic (Adt): 19,000 vehicles Autos: 15
Peak Hour Percentage: 10% Medium Trucks (2 Axles): 15
Peak Hour Volume: 1,900 vehicles Heavy Trucks (3+ Axles): 15
Vehicle Speed: 55 mph Vehicle Mix
Near/Far Lane Distance: 54 feet Vehicle Type I Day !Evening! Night I Daily
Site Data Autos: 80.0% 7.0% 13.0% 96.00% -
Barrier Height: 0.0 feet Medium Trucks: 80.0% 7.0% 13.0% 2.00%
Barrier Type (0-Wal!, 1-Berm): 0.0 Heavy Trucks: 80.0% 7.0% 13.0% 2.00%
Centerline Dist. to Barrier: 100.0 feet Noise Source Elevations (in feet)
Centerline Dist. to Observer: 100.0 feet Autos: 0.000 Barrier Distance to Observer: 0.0 feet Medium Trucks: 2.297
Observer Height (Above Pad): 5.0 feet Heavy Trucks: 8.006 Grade Adjustment: 0.0
Pad Elevation: 0.5 feet
Road Elevation: 0.0 feet Lane Equivalent Distance (in feet)
Road Grade: 0.0% Autos: 96.443
Left View: -90.0 degrees Medium Trucks: 96.339
Right View: 90.0 degrees Heavy Trucks: 96.319
FHWA Noise Model Calculations
Vehicle Type I REMEL I Traffic Flow I Distance I Finite Road I Fresnel I Barrier Atten I Berm Atten
Autos: 72.73 -0.10 -4.38 -1.20 -4.75 0.000 0.000
Medium Trucks: 79.85 -16.91 -4.38 -1.20 -4.86 0.000 0.000
Heavy Trucks: 83.81 -16.91 -4.37 -1.20 -5.14 0.000 0.000
Unmitigated Noise Levels (without Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 67.0 65.3 60.7 58.6 66.6 66.9
Medium Trucks: 57.4 55.6 51.0 49.0 56.9 57.2
Heavy Trucks: 61.3 59.6 55.0 52.9 60.9 61.2
Vehicle Noise: 68.4 66.7 62.1 60.0 68.0 68.3
Mitigated Noise Levels (with Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 67.0 65.3 60.7 58.6 66.6 66.9
Medium Trucks: 57.4 55.6 51.0 49.0 56.9 57.2
Heavy Trucks: 61.3 59.6 55.0 52.9 60.9 61.2
Vehicle Noise: 68.4 66.7 62.1 60.0 68.0 68.3
Thursday, April 16, 2009
FHWA-RD-77-108 HIGHWAY NOISE PREDICTION MODEL (CALVENO)
Scenario: Second Floor Facade Project Name: Robertson Ranch PA 22
Road Name: Cannon Road Job Number: 6679
Lot Number: Northwest Corner Analyst: J.Stephens
SITE SPECIFIC INPUT DATA NOISE MODEL INPUTS
Highway Data Site Conditions (Hard= 10, Soft= 15)
Average Daily Traffic (Adt): 19,000 vehicles Autos: 15
Peak Hour Percentage: 10% Medium Trucks (2 Axles): 15
Peak Hour Volume: 1,900 vehicles Heavy Trucks (3+ Axles): 15
Vehicle Speed: 55 mph Vehicle Mix
Near/Far Lane Distance: 54 feet Vehicle Type I Day J EveningJ Night I Daily
Site Data Autos: 80.0% 7.0% 13.0% 96.00%
Barrier Height: 0.0 feet Medium Trucks: 80.0% 7.0% 13.0% 2.00%
Barrier Type (0-Wa/1, 1-Berm): 0.0 Heavy Trucks: 80.0% 7.0% 13.0% 2.00%
Centerline Dist. to Barrier: 102.0 feet Noise Source Elevations (in feet)
Centerline Dist. to Observer: 102.0 feet Autos: 0.000 Barrier Distance to Observer: 0.0 feet Medium Trucks: 2.297
Observer Height (Above Pad): 14.0 feet Heavy Trucks: 8.006 Grade Adjustment: 0.0
Pad Elevation: 0.5 feet
Road Elevation: 0.0 feet Lane Equivalent Distance (in feet)
Road Grade: 0.0% Autos: 99.425
Left View: -90.0 degrees Medium Trucks: 99.116
Right View: 90.0 degrees Heavy Trucks: 98.576
FHWA Noise Model Calculations
Vehicle Type I REMEL I Traffic Flow I Distance I Finite Road I Fresnel I Barrier Atten I Berm Atten
Autos: 72.73 -0.10 -4.58 -1.20 -12. 70 0.000 0.000
Medium Trucks: 79.85 -16.91 -4.56 -1.20 -13.00 0.000 0.000
Heavy Trucks: 83.81 -16.91 -4.53 -1.20 -13. 77 0.000 0.000
Unmitigated Noise Levels (without Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.8 65.1 60.5 58.4 66.4 66.7
Medium Trucks: 57.2 55.4 50.9 48.8 56.7 57.0
Heavy Trucks: 61.2 59.4 54.9 52.8 60.7 61.0
Vehicle Noise: 68.2 66.5 61.9 59.8 67.8 68.1
Mitigated Noise Levels (with Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.8 65.1 60.5 58.4 66.4 66.7
Medium Trucks: 57.2 55.4 50.9 48.8 56.7 57.0
Heavy Trucks: 61.2 59.4 54.9 52.8 60.7 61.0
Vehicle Noise: 68.2 66.5 61.9 59.8 67.8 68.1
Thursday, April 16, 2009
FHWA-RD-77-108 HIGHWAY NOISE PREDICTION MODEL (CALVENO)
Scenario: Second Floor Facade Project Name: Robertson Ranch PA 22
Road Name: Cannon Road Job Number: 6679
Lot Number: Northeast Corner Analyst: J.Stephens
SITE SPECIFIC INPUT DATA NOISE MODEL INPUTS
Highway Data Site Conditions (Hard= 10, Soft= 15)
Average Daily Traffic (Adt): 19,000 vehicles Autos: 15
Peak Hour Percentage: 10% Medium Trucks (2 Axles): 15
Peak Hour Volume: 1,900 vehicles Heavy Trucks (3+ Axles): 15
Vehicle Speed: 55 mph Vehicle Mix
Near/Far Lane Distance: 54 feet Vehicle Type I Day IEveningl Night I Daily
Site Data Autos: 80.0% 7.0% 13.0% 96.00%
Barrier Height: 0.0 feet Medium Trucks: 80.0% 7.0% 13.0% 2.00%
Barrier, Type (0-Wa/1, 1-Berm): 0.0 Heavy Trucks: 80.0% 7.0% 13.0% 2.00%
Centerline Dist. to Barrier: 100.0 feet Noise Source Elevations (in feet)
Centerline Dist. to Observer: 100.0 feet Autos: 0.000 Barrier Distance to Observer: 0.0 feet Medium Trucks: 2.297 Observer Height (Above Pad): 14.0 feet Heavy Trucks: 8.006 Grade Adjustment: 0.0
Pad Elevation: 0.5 feet
Road Elevation: 0.0 feet Lane Equivalent Distance (in feet)
Road Grade: 0.0% Autos: 97.372
Left View: -90.0 degrees Medium Trucks: 97.056
Right View: 90.0 degrees Heavy Trucks: 96.505
FHWA Noise Model Calculations
Vehicle Type I REMEL I Traffic Flow I Distance I Finite Road I Fresnel I Barrier Atten I Berm Atten
Autos: 72.73 -0.10 -4.45 -1.20 -12.68 0.000 0.000
Medium Trucks: 79.85 -16.91 -4.42 -1.20 -12.99 0.000 0.000
Heavy Trucks: 83.81 -16.91 -4.39 -1.20 -13. 77 0.000 0.000
Unmitigated Noise Levels (without Topo and barrier attenuation)
Vehicle Type Leq Peak Hour LeqDay Leq Evening Leq Night Ldn CNEL
Autos: 67.0 65.2 60.7 58.6 66.5 66.8
Medium Trucks: 57.3 55.6 51.0 48.9 56.9 57.2
Heavy Trucks: 61.3 59.6 55.0 52.9 60.9 61.2
Vehicle Noise: 68.4 66.6 62.1 60.0 67.9 68.2
Mitigated Noise Levels (with Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 67.0 65.2 60.7 58.6 66.5 66.8
Medium Trucks: 57.3 55.6 51.0 48.9 56.9 57.2
Heavy Trucks: 61.3 59.6 55.0 52.9 60.9 61.2
Vehicle Noise: 68.4 66.6 62.1 60.0 67.9 68.2
Thursday, April 16, 2009
FHWA-RD-77-108 HIGHWAY NOISE PREDICTION MODEL (CALVENO)
Scenario: Third Floor With Wall Project Name: Robertson Ranch PA 22
Road Name: Cannon Road Job Number: 6679
Lot Number: Northwest Corner Analyst: J.Stephens
SITE SPECIFIC INPUT DATA NOISE MODEL INPUTS
Highway Data Site Conditions (Hard= 10, Soft= 15)
Average Daily Traffic (Adt): 19,000 vehicles Autos: 15
Peak Hour Percentage: 10% Medium Trucks (2 Axles): 15
Peak Hour Volume: 1,900 vehicles Heavy Trucks (3+ Axles): 15
Vehicle Speed: 55 mph Vehicle Mix
Near/Far Lane Distance: 54 feet Vehicle Type I Day jEveningj Night I Daily
Site Data Autos: 80.0% 7.0% 13.0% 96.00%
Barrier Height: 0.0 feet Medium Trucks: 80.0% 7.0% 13.0% 2.00%
Barrier Type (0-Wa/1, 1-Berm): 0.0 Heavy Trucks: 80.0% 7.0% 13.0% 2.00%
Centerline Dist. to Barrier: 102.0 feet Noise Source Elevations (in feet)
Centerline Dist. to Observer: 102.0 feet Autos: 0.000 Barrier Distance to Observer: 0.0 feet Medium Trucks: 2.297 Observer Height (Above Pad): 23.0 feet Heavy Trucks: 8.006 Grade Adjustment: 0.0
Pad Elevation: 0.5 feet
Road Elevation: 0.0 feet Lane Equivalent Distance (in feet)
Road Grade: 0.0% Autos: 101.130
Left View: -90.0 degrees Medium Trucks: 100.621
Right View: 90.0 degrees Heavy Trucks: 99.574
FHWA Noise Model Calculations
Vehicle Type I REMEL I Traffic Flow I Distance I Finite Road I Fresnel I Barrier Atten I Berm Atten
Autos: 72.73 -0.10 -4.69 -1.20 -19.89 0.000 0.000
Medium Trucks: 79.85 -16.91 -4.66 -1.20 -20.39 0.000 0.000
Heavy Trucks: 83.81 -16.91 -4.59 -1.20 -21.63 0.000 0.000
Unmitigated Noise Levels (without Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.7 65.0 60.4 58.3 66.3 66.6
Medium Trucks: 57.1 55.3 50.8 48.7 56.6 56.9
Heavy Trucks: 61.1 59.4 54.8 52.7 60.7 61.0
Vehicle Noise: 68.1 66.4 61.8 59.7 67.7 68.0
Mitigated Noise Levels (with Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.7 65.0 60.4 58.3 66.3 66.6
Medium Trucks: 57.1 55.3 50.8 48.7 56.6 56.9
Heavy Trucks: 61.1 59.4 54.8 52.7 60.7 61.0
Vehicle Noise: 68.1 66.4 61.8 59.7 67.7 68.0
Thursday, April 16, 2009
FHWA-RD-77-108 HIGHWAY NOISE PREDICTION MODEL (CALVENO)
Scenario: Third Floor With Wall Project Name: Robertson Ranch PA 22
Road Name: Cannon Road Job Number: 6679
Lot Number: Northeast Corner Analyst: J.Stephens
SITE SPECIFIC INPUT DATA NOISE MODEL INPUTS
Highway Data Site Conditions (Hard= 10, Soft= 15)
Average Daily Traffic (Adt): 19,000 vehicles Autos: 15
Peak Hour Percentage: 10% Medium Trucks (2 Axles): 15
Peak Hour Volume: 1,900 vehicles Heavy Trucks (3+ Axles): 15
Vehicle Speed: 55 mph Vehicle Mix
Near/Far Lane Distance: 54 feet Vehicle Type I Day !Evening! Night I Daily
Site Data Autos: 80.0% 7.0% 13.0% 96.00%
Barrier Height: 0.0 feet Medium Trucks: 80.0% 7.0% 13.0% 2.00%
Barrier Type (0-Wa/1, 1-Berm): 0.0 Heavy Trucks: 80.0% 7.0% 13.0% 2.00%
Centerline Dist. to Barrier: 100.0 feet Noise Source Elevations (in feet)
Centerline Dist. to Observer: 100.0 feet Autos: 0.000 Barrier Distance to Observer: 0.0 feet Medium Trucks: 2.297 Observer Height (Above Pad): 23.0 feet Heavy Trucks: 8.006 Grade Adjustment: 0.0
Pad Elevation: 0.5 feet
Road Elevation: 0.0 feet Lane Equivalent Distance (in feet)
Road Grade: 0.0% Autos: 99.112
Left View: -90.0 degrees Medium Trucks: 98.593
Right View: 90.0 degrees Heavy Trucks: 97.525
FHWA Noise Model Calculations
Vehicle Type I REMEL I Traffic Flow I Distance I Finite Road I Fresnel I Barrier Atten I Berm Atten
Autos: 72.73 -0.10 -4.56 -1.20 -19.84 0.000 0.000
Medium Trucks: 79.85 -16.91 -4.53 -1.20 -20.34 0.000 0.000
Heavy Trucks: 83.81 -16.91 -4.46 -1.20 -21.61 0.000 0.000
Unmitigated Noise Levels (without Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.9 65.1 60.5 58.5 66.4 66.7
Medium Trucks: 57.2 55.5 50.9 48.8 56.8 57.1
Heavy Trucks: 61.2 59.5 54.9 52.8 60.8 61.1
Vehicle Noise: 68.3 66.5 62.0 59.9 67.8 68.1
Mitigated Noise Levels (with Topo and barrier attenuation)
Vehicle Type Leq Peak Hour Leq Day Leq Evening Leq Night Ldn CNEL
Autos: 66.9 65.1 60.5 58.5 66.4 66.7
Medium Trucks: 57.2 55.5 50.9 48.8 56.8 57.1
Heavy Trucks: 61.2 59.5 54.9 52.8 60.8 61.1
Vehicle Noise: 68.3 66.5 62.0 59.9 67.8 68.1
Thursday, April 16, 2009
APPENDIXC
INTERIOR NOISE REDUCTION CALCULATIONS
APPENDIX D
STATIONARY NOISE SOURCE CALCULATIONS
STATIONARY SOURCE NOISE PREDICTION MODEL
Source: Mechanical Room
Observer Location: Southern Prop Line
Project Name: Robertson Ranch PA 22
Job Number: 6679
Noise Distance to Observer
Noise Distance to Barrier:
Barrier Distance to Observer:
Noise Height:
Observer Height (Above Pad):
Observer Elevation:
Noise Source Elevation:
Drop Off Coefficient:
Noise Level
Reference (Sample)
Distance Attenuation
Shielding (Barrier Attenuation)
Adjusted (Distance + Barrier)
Thursday, April 16, 2009
215.0 feet
210.0 feet
5.0 feet
15.0 feet
5.0 feet
0.0 feet
0.0 feet
Analyst: J.T. Stephens
NOISE MODEL INPUTS
Barrier Height:
Barrier Type (0-Wa/1, 1-Berm):
Barrier Breaks Line of Sight:
Wall Located at Noise Source Elevation:
16.0 feet
0.0
Yes
No
20.0 (20 = 6 dBA per doubling of distance, 15 = 4.5 dBA per doubling of distance)
NOISE MODEL PROJECTIONS
Distance (feet) Leq
15.0 82.0
215.0 -23.1
-16.2
215.0 42.7